The present invention relates to safety guards for use at work areas to deflect materials ejected from the work areas.
In various machining operations, such as grinding, buffing, polishing, drilling, milling, and the like, if often happens that broken tools, coolant etc., are ejected from the work area of a machine and present a hazard to an operator of the machine or other nearby personnel. In an attempt to minimize and hopefully prevent injuries caused by such ejected materials, and for other reasons, the Occupational Health and Safety Act of 1970 was enacted. The Occupational Health and Safety Act requires, in part, that one or more methods of machine guarding be provided to protect the operator and other employees in the area from hazards, such as those created by point of operation, rotating parts, or flying chips.
It is known to provide protection against flying chips and the like by means of a shield extending across the front of a work area. Such shields are generally mounted within or in close proximity to the work area, and present their own set of problems, in that when the shield is moved aside, it often happens that the mount for the shield or the shield itself impedes access to the area. Further, to change a setup for a workpiece, it often is necessary to first reposition the shield mount to be clear of the new setup. Quick change mounts, such as those having magnetic bases, while intended to alleviate the aforementioned problems, scratch and tend to be bumped off the machine mounting surface, sometimes into the work area itself. Thus, protective shields are often inconvenient to use and adjust, which can result in improper or even lack of use of such shields.
An exemplary known machine guard is disclosed by U.S. Pat. No. 4,043,701, issued on Aug. 23, 1977 to Ben E. Jaeger, the present inventor and the teachings of which are specifically incorporated herein by reference. The transparent guard or shield of said patent is well adapted to be positioned between a work area of a machine tool and an operator station to protect the operator and others who may be nearby, and is carried on a universal arm so as to be readily and conveniently moved fully away from the work area to accommodate unimpeded access to the work area and setup. However, a single universal arm carries the transparent shield, so the shield is limited to be of a size and weight as can be properly and securely supported by the arm. Also, the universal arm is anchored to the shield through a handle that is gripped by an operator to move the shield, as a result of which the shield is part of the retention structure for the handle and subject to forces that can damage the shield when the handle is gripped to move the shield assembly. Further, because a single arm supports the shield, undesirable oscillation of the shield on the end of the arm may occur.
Accordingly, an object of the present invention is to provide an improved guard for a work area of a machine tool, that effectively blocks material ejected from the work area from entering an operator station.
Another object is to provide such a guard, which is easily and readily movable and adjustable between positions adjacent to and remote from the work area.
A further object is to provide such a guard that is easily mountable on various types of machine tools at convenient locations remote from work areas thereof.
A still further object is to provide such a guard that is of a transparent material and configured to effectively extend across the front of the work area of a machine tool.
Still another object is to provide such a guard having a planar portion for undistorted viewing of the work area therethrough.
Yet another object is to provide such a guard that is mounted on a pair of universal arms and that includes a pair of handles to facilitate operator movement thereof between various positions.
In accordance with the present invention, a safety guard assembly for a machine tool comprises a unitary transparent guard having a generally planar portion and rib means extending along and out of the plane of the planar portion for stiffening the planar portion. Also included is at least one arm having a plurality of movable joints. The at least one arm is coupled at one end to the guard and is mountable at an opposite end remote from a work area of the machine tool. The at least one arm is movable to accommodate supporting the guard at positions in front of the work area with the planar portion of the guard between the work area and an operator station, and at positions remote from the work area. At least one handle is coupled to the guard and grippable by an operator of the machine tool to move the guard on the at least one arm between the positions.
In a preferred embodiment of the invention, the guard planar portion is generally rectangular and the rib means comprises a pair of ribs extending along respective upper and lower ends of the planar portion. The planar portion has a front side and a rear side and the ribs extend outward and rearward away from the planar portion. Also, the at least one arm comprises a pair of arms, each coupled at the one end to the guard and each being mountable at an opposite end remote from the work area. Advantageously, the opposite ends of the pair of arms are mountable remote from and on opposite sides of the work area. In addition, the at least one handle comprises a pair of handles, and the handles and the one ends of the arms are coupled to the guard on respective opposite sides of the guard.
It is contemplated that the movable joints of each arm accommodate pivotal and rotational movement of the one end of the arm with respect to the opposite end of the arm, and included is a pair of brackets connected to respective opposite sides of the guard. The two arms are each connected at the one end thereof to respective ones of the brackets, and the two handles are connected to respective ones of the brackets.